Polyethylene terephthalate polymer composition containing at least 0.5 weight percent of a sulfonated pyrrole



United States Patent 3,507,835 POLYETHYLENE TEREPHTHALATE POLYMER COMPOSITION CONTAINING AT LEAST 0.5 WEIGHT PERCENT OF A SULFONATED PYRROLE Robert W. Stackman, Morris Township, Morris County,

NJ., and Donald E. Sargent, Schenectady, N.Y., assignors to Celanese Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 29, 1966, Ser. No. 605,570 Int. Cl. C08g 17/14 US. Cl. 26075 8 Claims ABSTRACT OF THE DISCLOSURE A polymer composition having improved dyeability properties comprising a synthetic linear thermoplastic polymer and at least 0.5 weight percent of a sulfonated pyrrole.

This invention relates to compositions and shaped articles made therefrom having improved dyeability properties and methods of producing these products. More particularly, the invention is directed to compositions of synthetic polymers, preferably synthetic linear thermoplastic polymers containing a specific type of sulfonated pyrrole which in turn can provide articles such as films, fibers and the like, having an afiinity for basic dyes.

Successful methods have been suggested in the past to improve the dyeability of shaped articles made from synthetic polymers such as fibers, fabrics or films especially utilizing basic dyes to provide brighter colors and also to permit cross dyeing of the articles. These methods utilize the techniques of incorporating sulfonated monomers into synthetic polymers such as acetate, triacetate, acrylic, modacrylic, polyester, nylon, polypropylene and the like to provide copolymers. Typical of this procedure is U.S. Patent 3,018,272 which describes the process of producing basic dyeable polyesters having incorporated therein as monomers, the sulfonated monomers. Although these copolymers provide satisfactory basic dyeable materials, other suitable materials are being sought to provide improvements in dyeability for the synthetic linear thermoplastic polymers.

It has now been discovered that a certain type of sulfonated pyrrole can be incorporated, i.e., in the form of a copolymer or additive into synthetic polymers, to improve the basic dye uptake of these polymers and end products made therefrom. The specific type of sulfonated pyrrole which can be utilized can be represented by the following formula:

lrrSOgX wherein each R, individually, represents hydrogen or an alkyl group containing from 1 to 6 carbon atoms; each R, individually, represents hydrogen and an alkyl group containing from 1 to 6 carbon atoms; Ar represents an arylene radical and X represents a metal to satisfy the valence of the sulfonate group and preferably represents an alkali metal. It is usually desirable to use at least about 0.5 weight percent of the sulfonated pyrrole based on the total polymer to provide basic dye sites. Polymer compositions having a sulfonated pyrrole content lower than 0.5 weight percent will have only a relatively low afiinity for basic dyes. Polymer compositions containing about 10 Weight percent of the sulfonated pyrrole compound have a very high afiinity for basic dyes. Higher 3,507,835 Patented Apr. 21, 1970 concentrations will not lead to appreciable increases in basic dyeability and in general may unduly affect tenacity in the shaped articles. The sulfonated pyrrole compound concentrations in the range from 2 to 8 weight percent of the total polymer, are preferred. The sulfonated pyrrole compound can be added to the polymerization reaction or to the starting materials such as are used in the ester interchange reaction if this is required. If it is desired that the presence of these sulfonated pyrrole compounds in the polymer be in the form of copolymers, the addition can occur very early in the polymerization or in the initial starting materials. If it is desired to have the sulfonated pyrrole compounds in the polymer as merely additives then the materials should be added at the later stages of polymerization.

The sulfonated pyrrole compound can be prepared according to the procedure described in Journal Fiir Praktische Chemie 17, 213 (1962). This procedure involves the typical reaction such as equimolar amounts of the sodium salt of sulfanilic acid and diethyl diacetyl succinate in acetic acid. Under these conditions, l-(psodium sulfophenyl)-2,5-dimethyl-3,4dicarboethoxy pyrrole is produced.

In the preparation of the sulfonated pyrrole compounds, typical starting materials include, among others: diethyl diacetyl succinate; dipropyl dipropionyl succinate; di(nbutyl) di(n-butyryl) succinate; di(n-pentyl) diisovaleryl succinate; di(n-hexyl) di(ncaproyl) succinate; and the like. Typical alkali salts of sulfanilic acid include, among others: sodium 4-aminophenyl sulfonate; potassium 4- arninophenyl sulfonate; lithium 4-aminophenyl sulfonate; sodium 4-aminonaphthyl l-sulfonate; potassium 3-aminonaphthyl l-sulfonate; lithium S-aminonaphthyl l-sulfonate, alkyl substituted sulfanilic acid alkali salts; alkyl substituted aminonaphthyl sulfonic acid alkali salts; halogen substituted sulfanilic acid alkali salts and the like. The metals which can be used to satisfy the valence of the sulfonate group can include the alkali metals such as sodium, potassium, lithium and the like, alkali earth metals such as calcium, strontium, barium and the like or metals such as magnesium, cobalt, manganese and the like. The preferred metals, however, include the alkali metals.

The new compositions of the present invention, i.e., containing sulfonated pyrrole compounds and polymerized synthetic linear thermoplastic polymer, are useful in the production of shaped articles by extrusion, molding, casting or the like. These shaped articles in turn may be formed in fibers (filaments and staple), fabrics, ornaments, films and the like.

The term linear thermoplastic polymer as used herein includes polymeric polymethylene terephthalates, especially preferred is polyethylene terephthalate. Other polymers which can be utilized herein are polyalkylene terephthalate containing modifiers such as dibasic acids including among others; isophthalic acid, sebacic acid, adipic acid and the like. Cyclic glycols can also be substituted for the alkylene glycols in the linear terephthalate polymers. Other polymers included herein are polyamides such as polyhexamethylene adipamide, polyhexamethylene sebacamide, polytetramethylene sebacamide, polytetramethylene adipamide and the like. Other polyamides include those prepared from di(4-amino-cyclohexyl) ethane or 1,6-(4-aminocyclohexyl)hexane as the diamine components. Additional polymers include polypropylene, polybutenes and the like. As is known, the intrinsic viscosities of the above-described polymers should be in excess of 0.2, preferably in the range from 0.4 to 1.0 when used for producing textile and industrial products. The measurement of intrinsic viscosity is conducted by utilization of a one-weight percent polymer solution in a mixture of 58.8 parts of phenol and 41.2 parts of trichlorophenol.

Various other materials may be present in the present new compositions. For example, such ester exchange catalysts as salts of calcium, magnesium, manganese and the like and such polymerization catalysts as antimony oxide, antimonic acid or the like, may be used. In addition, pigments, delusterants, or other additives such as titanium dioxide or barium carbonate.

The yarns or filaments produced in accordance with the present invention are suitable for the usual textile applications. They may be employed in the knitting or weaving of fabrics of all types as well as in the production of nonwoven, felt-like products produced by known methods. Their physical properties closely parallel those of their related non-modified polymer fibers. However, they have particular sensitivity toward basic dyes. By a basic dye is meant a colored cationic organic substance such as those containing sulfonium, oxonium or quaternary ammonium functional groups. Among the basic types which may be applied to the filaments formed in accordance with the present invention may be mentioned Victoria Green WB (C.I. 657); Thodiamine B (Cl. 749); Brilliant Green B (01. 662); Victoria Pure Blue BO(Pr 198); Sevron Blue B; and the like. The dyes are preferably applied from an aqueous solution at a temperature between 80 and 125 C.

Filaments and films, i.e., shaped structures which have at least one dimension relatively very small and at least one dimension relatively large, are the preferred structures of the present invention. Such structures of the polymer mixtures of this invention are permeated uniformly throughout by basic dyes applied from hot aqueous solution. The penetration of dyes is an important characteristic since poor resistance of fading and loss of color through rubbing or abrasion is a known characteristic of structures which retain dye only at their surfaces.

The following examples will serve to illustrate the invention:

EXAMPLE 1 In a reaction flask, 19.5 grams (0.1 mol) of the sodium salt of sulfanilic acid and 25.8 grams (0.1 mol) diethyl diacetyl succinate are heated in 800 milliliters of acetic acid for 2 hours at 80 C. The reaction product (l-(psodium sulfophenyl)-2,5-dimethyl-3,4-dicarboethoxy pyrrole) is cooled and ether added thereto. The reaction product is precipitated and recovered by filtration. The product is recrystallized in a small amount of acetone to obtain a white salt having a melting point of 310- 311 C. The amount of product obtained was 35 grams representing a yield of 84 percent.

EXAMPLE 2 To a 500 ml. three-necked flask equipped with stirrer, nitrogen inlet and distillation head were added 3.89 g. of l-(p-sodium sulfophenyl) 2,5 dimethyl-3,4-dicarboethoxy pyrrole in ml. of ethylene glycol, 0.07 g. antimonic acid and 100 g. bis(hydroxyethyl) terephthalate. The flask was flushed three times with nitrogen, then heated to 235 C., at which temperature all the material had melted to form a clear solution. The temperature was increased over a period of one hour to 270 C. The pressure was then slowly lowered by means of a vacuum pump to 0.25 mm. Hg while the temperature was increased to 290 C. The polymerizing mixture was stirred 4 at 290 C. and 0.25 mm. Hg pressure for minutes. At the end of this period, the vacuum was released and the polymer allowed to cool. The recovered polymer had a crystalline melting point of 248251 C. and had an inherent viscosity of 0.47 determined in a mixture of 58.8 parts phenol and 41.2 parts trichlorophenol. The polymer was spun at 285 C. from a melt index apparatus and oriented by stretching over a heated surface. A sample of the oriented fiber Was dyed in a Sevron Blue B basic dye bath for one hour at C. The fibers dyed to a deep shade of blue having good Washfastness properties.

In a similar manner as above, polyhexamethylene adipamide can be substituted for polyethylene terephthalate.

It is understood that the foregoing description is merely illustrative of preferred embodiments of the invention of which many variations may be made by those skilled in the art within the scope of the following claims without departing from the spirit thereof.

What is claimed is:

1. A polymer composition having improved dyeability properties consisting essentially of a synthetic linear terephthalate polymer and at least 0.5 weight percent of a sulfonate having the formula:

wherein R, each individually, represents hydrogen and an alkyl group containing from 1 to 6 carbon atoms, R each individually, represents hydrogen and an alkyl group containing from 1 to 6 carbon atoms, Ar represents a phenylene or a naphthalene radical and X represents a metal to satisfy the available valence selected from the group consisting of an alkali metal, an alkali earth metal, magnesium, cobalt, and manganese.

2. The composition of claim 1 wherein X represents an alkali metal.

3. The composition of claim 2 wherein the sulfonate is present in amounts ranging from 2 to 8 weight percent.

4. The composition of claim 2 wherein the sulfonate present is l-(p-sodium sulfophenyl)-2,5-dimethyl-3,4- dicarboethoxy pyrrole.

5. The composition of claim 1 in the form of a shaped article.

6. The composition of claim 2 in the form of a shaped article.

7. The composition of claim 3 in the form of a shaped article.

8. The composition of claim 4 in the form of a shaped article.

References Cited UNITED STATES PATENTS 3,018,272 1/1962 Griffing 260-75 WILLIAM H. SHORT, Primary Examiner LESTER L. LEE, Assistant Examiner US. Cl. X.R. 

